Can she talk? Could she tell you if she were having bad dreams? She is old enough to realize that she may can get some control by screaming, though, too.
With all five kids, we went throught this, and the remedy wasn't always the same...
Some were manipulators.
Some were scared.
Some were having bad dreams, etc.
She could be genuinely scared...
Or...they all do it--it's called testing boundaries. If you feel this is what she's doing, then be consistent in whatever discipine or consequence you choose, and be calm and loving with her always. Something negative should take place when she won't go to sleep. This is a hard situation, though, and it really depends upon the kid, too. (The youngest of my five has been the worst, and I admit I have babied him far too much! I know too well, now, how quickly they grow up!)
Deciding what kind of cry she has could help you decide what course of action to take. As mothers, we tend to intuitively know a hurt cry from a scared cry, and pain cry from a hunger cry... you know. If she seems truly scared, you might have to talk with her about it or find out about dreams she's having?? For us, there have been times of both with different kids... Some would do it just to manipulate, LOL...others would be truly scared, and we would find out they were having nightmares, or the window looked scary at night. Bless their hearts.
I wonder if you could try training her at some other part of the day, when it's not bedtime. Get creative? Teach her it's not bad to be in it??? maybe a fun activity she enjoys and let it take place in the bed?
Then perhaps bedtime could be better?
One very stubborn (still is today) child we have pulled this each night at bedtime. Finally, we had exhausted all disciplinary options, hugged and kissed, etc. We went to bed, turned out all the mights, and left her standing there alone in the dark. After a few nights of this, she decided she would rather go to bed. ; )
I will pray you can get to the bottom of her bedtime struggles!
Blessings,
H.